(19) |
 |
|
(11) |
EP 0 143 508 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
|
12.02.1986 Bulletin 1986/07 |
(43) |
Date of publication A2: |
|
05.06.1985 Bulletin 1985/23 |
(22) |
Date of filing: 18.07.1984 |
|
|
(84) |
Designated Contracting States: |
|
BE DE FR GB NL SE |
(30) |
Priority: |
31.10.1983 US 547304
|
(71) |
Applicant: ATLANTIC RICHFIELD COMPANY |
|
() |
|
(72) |
Inventors: |
|
- Dehm, David C.
()
- Lawson, H. Frank
()
|
|
|
|
(54) |
Additive for water-base drilling fluid and process |
(57) An additive for water-base drilling fluid compositions used for drilling subterranean
wells is disclosed. In one embodiment, the additive is a sulfonated copolymer of recurring
units of a maleimide monomer and recurring units of a vinyl monomer. In another embodiment,
the additive is a sulfonated terpolymer of recurring units of a maleimide monomer,
recurring units of a vinyl monomer, and recurring units of a carboxyl-containing monomer.
Water-base drilling fluids compositions which contain the additive and a process for
drilling subterranean wells therewith are also disclosed.